In the context of the design of aeronautical structures regarding accidental events, we are here analyzing and comparing the shear failure of two aluminum alloys, namely AA2024 and AA7175, under high strain loading. With this aim in view, two experiments were carried out: (i) high strain rate shear compression of hat shaped structures, and (ii) impact test on the side of double notched plates. The fractured surfaces of post-mortem specimens were observed using optical and scanning electron microscopes (SEM) in order to identify the failure mechanisms.